GLACIERS OF ALASKA 11 tern from the unnamed second glacier of Alsek River to the terminus of Hidden or Nuna-tak Glacier of Russell Fiord, the valley glaciers averaging two to five miles in width and reaching elevations of from 2000 to 3000 feet on the highest divides.1 This region is one of glacier highways from Yakutat Bay to the Alsek over the Nunatak or Fourth Glaciers. Several hundred prospectors utilized the Nunatak (Third Glacier) route in 1898, among them the Messrs. Hill from whose sketches the United States Geological Survey has compiled a map,2 which shows the seven or more great valley glaciers reaching the western or Kaskawulsh branch of Alsek River, and the otherwise unexplored glaciers east of Mounts Seattle and Hubbard. A complex system of through glaciers connects the Upper Alsek glaciers with the Nunatak and Hubbard Glaciers of the Yakutat Bay region, the distance over the ice being forty miles or more. Glaciers of Yakvtat Bay and Mi. St. Elias. The Hidden, Fourth, Nunatak, Variegated, Hubbard, Haenke, Turner, Black, Galiano, Atrevida, and Lucia Glaciers of Yakutat Bay, Disenchantment Bay, and Russell Fiord, and the Hayden, Marvine, Seward, Agassiz, Libbey, Tyndall, and Guyot tributaries of Malaspina Glacier are to be so fully described in later chapters that they will not be further discussed here. Glaciers North of the St. Elias Range. Throughout this loftiest part of the St. Elias Range, 10,000 to 19,000 feet, whose glaciers are still largely unexplored, there is an intricate system of through glaciers filling the valleys and passes. For 140 miles from Alsek to Copper River no one has ever yet crossed the range. A striking feature is the smaller number and size of glaciers on the north or leeward side of the range in contrast with the great number of large glaciers that cover the south or windward side in the Yakutat Bay and Mt. St. Elias regions. These ice-filled valleys of the main St. Elias Range include unexplored through glacier systems that extend from Yakutat Bay to the upper Alsek as well as to the headwater regions of the White, the Tanana', and the Copper Rivers. The Abruzzi party in 1897 named the Colombo, A. Q. Sella, and other glaciers north of Mt. St. Elias.3 The Kaskawulsh or O'Connor or Slims River Glacier is perhaps the northern terminus of the Hubbard through glacier system.4 Its two streams flow one to the Alsek and directly to the Pacific Ocean, the other to White and Yukon Rivers and Bering Sea. In 1899 and 1904 Kaskawulsh Glacier was retreating.6 Other north-flowing ice tongues of the St. Elias Range are the two Donjek River glaciers, 20 to 23 miles long, the Klutlan Glacier, and the Russell Glacier, shown on several maps fl and briefly described by Hayes in 1891,7 • Unpublished Map, 1906, Sheet 2846, Archives U. S. Coast and Geodetic Survey. » Alsek River Region, 1: 380,000, 1905, unpublished. • The Ascent of Mt. St. Elks, London, 1900, pp. 156-160. «Map of Kluane, White, and Alsek Rivers, Yukon Terr., Dept. of Int., Canada, 1905. • Brooks, A. H., 21st Ann. Rept., U. S. Geol. Survey, Part II, 1899-1900, PI. XLTTT. PI. XLV A, and p. 364. McConnelL R. G.. the Kluane Mining District, Geol. Survey of Canada, Ann. Rept., 1904^ Vol. XVI, pp. 2A, OA, 10A, and Map 894. «Nat. Geog. Mag., Vol. IV, 1892, PL 20. 21st Ann. Rept., U. S. Geol. Survey, 1899-1900, Part H, PI. XL1H. Map of Kluane, White and Alsek Rivera, Yukon Terr., Dept. of Int., Canada, 1905. Professional Paper 41, U. S. Geol. Survey, PL XX. Chitina Quadrangle, Map 601, Alaska, U. S. Geol. Survey; Nizina Special Quadrangle, Map 601B, Alaska, D. S. Geol. Survey. T Hayes, C. W., Nat. Geog. Mag., Vol. IV, 1892, pp. 151-154.